1. Field of the Invention
The present invention relates generally to microelectronic fabrications having formed therein terminal electrode structures. More particularly, the present invention relates to microelectronic fabrications having formed therein terminal electrode structures which provide enhanced passivation of the microelectronic fabrications and enhanced bondability to the terminal electrode structures.
2. Description of the Related Art
Microelectronic fabrications are formed from microelectronic substrates over which are formed patterned microelectronic conductor layers which are separated by microelectronic dielectric layers.
In conjunction with various means and configurations for interconnecting microelectronic fabrications of various varieties, it is common in the art of microelectronic fabrication to employ integral to individual microelectronic fabrications terminal electrode structures at locations within the individual microelectronic fabrications where the individual microelectronic fabrications are to be interconnected. Such terminal electrode structures are typically formed integral to the individual microelectronic fabrications while employing various metallurgy layers, which under certain circumstances may include solder interconnection layers, to which the various means and configurations for interconnecting the microelectronic fabrications may be connected.
While terminal electrode structures are thus desirable and clearly essential within the art of microelectronic fabrication for effectively providing electrical interconnections for various varieties of microelectronic fabrications which may be fabricated within the art of microelectronic fabrication, terminal electrode structures are nonetheless not entirely without problems in the art of microelectronic fabrication when fabricating microelectronic fabrications. In that regard, it is typically highly desirable within the art of microelectronic fabrication, but nonetheless not always readily achievable within the art of microelectronic fabrication, to provide within a microelectronic fabrication a terminal electrode structure which simultaneously provides enhanced passivation of microelectronic fabrication within which is formed the terminal electrode structure and enhanced bondability to the terminal electrode structure.
It is thus towards the goal of providing for use when fabricating a microelectronic fabrication a terminal electrode structure which simultaneously provides within the microelectronic fabrication an enhanced passivation of the microelectronic fabrication within which is formed the terminal electrode structure and enhanced bondability to the terminal electrode structure that the present invention is directed.
Various configurations and materials have been disclosed within the art of microelectronic fabrication for fabricating and testing, with desirable properties, terminal electrode structures within microelectronic fabrications.
For example, Agarwala et al., in U.S. Pat. No. 5,130,779, disclose: (1) a multi-layer solder layer terminal electrode structure with an enhanced aspect ratio for use within a microelectronic fabrication for directly interconnecting, with attenuated physical stress and strain, a pair of microelectronic substrates within the microelectronic fabrication; and (2) a method for forming the multi-layer solder layer terminal electrode structure with the enhanced aspect ratio for use within the microelectronic fabrication for directly interconnecting, with attenuated physical stress and strain, the pair of microelectronic substrates within the microelectronic fabrication. To realize the foregoing objects, the method for forming the multi-layer solder layer terminal electrode structure employs forming upon at least one terminal electrode solder layer employed within the multi-layer solder layer terminal electrode structure, prior to thermal reflow of the at least one terminal electrode solder layer: (1) a capping or encapsulant metal layer, or in the alternative; (2) a sidewall spacer layer, such that upon thermal reflow of the at least one terminal electrode solder layer the at least one terminal electrode solder layer is not susceptible to thermal reflow induced collapse.
In addition, Tsukamoto, in U.S. Pat. No. 5,640,052, discloses a terminal electrode structure for use when directly interconnecting a pair of microelectronic substrates within a microelectronic fabrication, where the terminal electrode structure provides for attenuated thermally induced physical stress and strain of the pair of microelectronic substrates with respect to the terminal electrode structure when directly interconnecting the pair of microelectronic substrates within the microelectronic fabrication while employing the terminal electrode structure. To realize the foregoing object, the terminal electrode structure employs a metal core layer having formed thereupon a solder terminal electrode layer which bridges to a pair of bond pads formed within the pair of microelectronic substrates, where the solder terminal electrode layer which bridges to the pair of bond pads formed within the pair of microelectronic substrates is formed with an hourglass shape.
Further, Strauss, in U.S. Pat. No. 5,719,449, disclose a flip chip integrated circuit microelectronic fabrication which employs therein a terminal electrode structure which provides for improved testability of the flip chip integrated circuit microelectronic fabrication. The flip chip integrated circuit microelectronic fabrication realizes the foregoing object by providing within the flip chip integrated circuit microelectronic fabrication a terminal metal layer which is fabricated to comprise a pair of interconnected bond pad layers, wherein: (1) one of the pair of interconnected bond pad layers serves as an electrical test bond pad layer terminal electrode structure within the flip chip integrated circuit microelectronic fabrication and has formed thereupon no additional metallurgy layers; and (2) a second of the pair of interconnected bond pad layers serves as an electrical interconnection bond pad layer and has formed thereupon a solder layer to provide an electrical interconnection terminal electrode structure within the flip chip integrated circuit microelectronic fabrication.
Finally, Wood et al., in U.S. Pat. No. 5,781,022, disclose an electrical test apparatus which provides for electrically testing an integrated circuit microelectronic fabrication die through contact of a probe which is integral to the electrical test apparatus with a bond pad terminal electrode structure which is integral to the integrated circuit microelectronic fabrication die, where neither the bond pad terminal electrode structure nor a passivation layer passivating a portion of the bond pad terminal electrode structure which is integral to the integrated circuit microelectronic fabrication die is damaged incident to electrically testing the integrated circuit microelectronic fabrication die with the electrical test apparatus. In order to realize the foregoing result, the electrical test apparatus employs the probe which comprises a nominally flat but nonetheless ridged probe surface which contacts the bond pad terminal electrode structure within the integrated circuit microelectronic fabrication die.
Desirable for use when fabricating microelectronic fabrications are additional terminal electrode structures which simultaneously provide within a microelectronic fabrication enhanced passivation of a microelectronic fabrication within which is formed the terminal electrode structure and enhanced bondability to the terminal electrode structure.
It is towards the foregoing objects that the present invention is directed.
A first object of the present invention is to provide a terminal electrode structure for use within a microelectronic fabrication, and a method for fabricating the terminal electrode structure for use within the microelectronic fabrication.
A second object of the present invention is to provide the terminal electrode structure and the method for fabricating the terminal electrode structure in accord with the first object of the present invention, wherein the terminal electrode structure provides enhanced passivation of the microelectronic fabrication within which is formed the terminal electrode structure and enhanced bondability to the terminal electrode structure.
A third object of the present invention is to provide the method for forming the terminal electrode structure in accord with the first object of the invention and the second object of the invention, which method is readily commercially implemented.
In accord with the objects of the present invention, there is provided by the present invention a terminal electrode structure for use when fabricating a microelectronic fabrication, and a method for fabricating the terminal electrode structure for use when fabricating the microelectronic fabrication.. To practice the method of the present invention, there is first provided a substrate. There is then formed over the substrate a patterned bond pad layer. There is also formed over the substrate a patterned passivation layer which passivates a series of edges of the patterned bond pad layer while leaving exposed a central portion of the patterned bond pad layer, where the patterned passivation layer has a series of protrusions within the patterned passivation layer over the series of edges of the patterned bond pad layer. There is then formed over the central portion of the patterned bond pad layer and bridging over the series of protrusions of the patterned passivation layer a first terminal electrode layer having an upper surface which is concave. Finally, there is then formed over the first terminal electrode layer a second terminal electrode layer having an upper surface which is other than concave, and preferably planar.
The method for fabricating the terminal electrode structure in accord with the present invention contemplates the terminal electrode structure fabricated in accord with the method for fabricating the terminal electrode structure in accord with the present invention.
The present invention provides a terminal electrode structure for use when fabricating a microelectronic fabrication, and a method for fabricating the terminal electrode structure for use when fabricating the microelectronic fabrication, wherein the terminal electrode structure provides enhanced passivation of the microelectronic fabrication within which is formed the terminal electrode structure and enhanced bondability to the terminal electrode structure. The present invention realizes the foregoing objects by employing when fabricating a terminal electrode structure within the microelectronic fabrication in accord with the present invention formed over a patterned bond pad layer the edges of which are passivated by a patterned passivation layer which in turn has a series of protrusions over the series of edges of the patterned bond pad layer a terminal electrode structure which comprises: (1) a first terminal electrode layer which is formed over the patterned bond pad layer within the microelectronic fabrication and bridging over the series of protrusion of the patterned dielectric passivation layer which passivates the series of edges of the patterned bond pad layer (to provide the enhanced passivation of the microelectronic fabrication), where the first terminal electrode layer has an upper surface which is concave; and (2) a second terminal electrode layer formed over the first terminal electrode layer, where the second terminal electrode layer has an upper surface which is other than concave, and preferably planar (to provide enhanced bondability to the terminal electrode structure).
The method of the present invention is readily commercially implemented. As will be clear, and as is illustrated within the Description of the Preferred Embodiment which follows, the present invention employs methods and materials as are otherwise generally known in the art of microelectronic fabrication, but employed within the context of specific process controls and process limitations to provide the present invention. Since it is a materials selection and process control which thus provides at least in part the present invention, rather than the existence of methods and materials which provides the present invention, the method of the present invention is readily commercially implemented.